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Comparison of Radiological Parameters between Normal and Patellar Dislocation Groups in Korean Population: A Rotational Profile CT-Based Study

View Article: PubMed Central - PubMed

ABSTRACT

Purpose: Patellofemoral instability is a common cause of anterior knee pain in adolescents and young adults. Most normal and pathological values for diagnosing patellofemoral instability are based on Western literature. We conducted this radiological study to determine normal values for different patellofemoral parameters in a Korean population and to evaluate their usefulness in diagnosis.

Materials and methods: We retrospectively reviewed the rotational profile computerized tomography (CT) scans of the patellar dislocation and control groups. Trochlear, patellar, rotational profile, and trochleo-patellar alignment parameters were compared between the groups. Receiver operating characteristic curves were drawn for significant parameters, and sensitivity and specificity were calculated for the cut-off values.

Results: There were 48 patients in the patellar dislocation group and 87 patients in the control group. In the control group and patellar dislocation group, the mean sulcus angle was 132.5° and 143.3°, respectively, trochlear depth was 6.04 mm and 3.6 mm, bisect offset was 56.4% and 99.9%, lateral patellar tilting was 9.8° and 19.2°, patellar facet asymmetry was 63.5% and 45.16%, and the tibial tuberosity-trochlear groove (TT-TG) distance was 10.91 mm and 27.16 mm, respectively.

Conclusions: The trochlear depth, bisect offset, patella tilting, and TT-TG distance were parameters that significantly contributed to patellar instability. Rotational profile CT can be considered a good diagnostic tool to assess all these parameters that help to identify anatomical aberration resulting in patellofemoral instability, thereby helping in formulating the most effective treatment plan.

No MeSH data available.


Bisect offset. (A) Patellar and trochlear computed tomography images were different. The trochlear bisect line was drawn on the slice with the best trochlear profile. (B) The trochlear bisect line was extended on the patellar image. Patellar lines were drawn on the slice with maximum patellar width. c: trochlear bisect line drawn on the trochlear axial image, a: patellar width, b: the width of the patella lateral to the trochlear bisect line. Bisect offset is b/a×100.
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f2-ksrr-28-302: Bisect offset. (A) Patellar and trochlear computed tomography images were different. The trochlear bisect line was drawn on the slice with the best trochlear profile. (B) The trochlear bisect line was extended on the patellar image. Patellar lines were drawn on the slice with maximum patellar width. c: trochlear bisect line drawn on the trochlear axial image, a: patellar width, b: the width of the patella lateral to the trochlear bisect line. Bisect offset is b/a×100.

Mentions: Alignment of the patella over the trochlea is an important aspect that affects patellar tracking and may have a causative role in patellofemoral dysfunction. It was measured on the same slice that morphologic features of the trochlea were measured. On this slice, a perpendicular line was drawn through the center of the trochlea intersecting with the posterior condylar line. Then, on the slice where the patella width was maximal, a line connecting the medial and lateral margins of the patella was drawn. If the posterior condylar line was drawn on a different slice than the slice with maximal patellar width, the posterior condylar line was copied to the slice where the patella width was maximal. Different angles were noted to best define the patella-trochlear articulation: 1) bisect offset: it was defined as the percentage of the patella lateral to the line through the center of the trochlea (Fig. 2), 2) lateral patella tilt angle: it was defined as the angle between the posterior condylar line and the line defining the maximal width of the patell, 3) Laurin angle: it is the angle between the lines drawn along the lateral patellar facet and the anterior margins of femoral trochlea. 4) congruence angle: it is comprised between a line bisecting the sulcus angle and a second line joining the apex of trochlear groove with the apex of the patella.


Comparison of Radiological Parameters between Normal and Patellar Dislocation Groups in Korean Population: A Rotational Profile CT-Based Study
Bisect offset. (A) Patellar and trochlear computed tomography images were different. The trochlear bisect line was drawn on the slice with the best trochlear profile. (B) The trochlear bisect line was extended on the patellar image. Patellar lines were drawn on the slice with maximum patellar width. c: trochlear bisect line drawn on the trochlear axial image, a: patellar width, b: the width of the patella lateral to the trochlear bisect line. Bisect offset is b/a×100.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5134791&req=5

f2-ksrr-28-302: Bisect offset. (A) Patellar and trochlear computed tomography images were different. The trochlear bisect line was drawn on the slice with the best trochlear profile. (B) The trochlear bisect line was extended on the patellar image. Patellar lines were drawn on the slice with maximum patellar width. c: trochlear bisect line drawn on the trochlear axial image, a: patellar width, b: the width of the patella lateral to the trochlear bisect line. Bisect offset is b/a×100.
Mentions: Alignment of the patella over the trochlea is an important aspect that affects patellar tracking and may have a causative role in patellofemoral dysfunction. It was measured on the same slice that morphologic features of the trochlea were measured. On this slice, a perpendicular line was drawn through the center of the trochlea intersecting with the posterior condylar line. Then, on the slice where the patella width was maximal, a line connecting the medial and lateral margins of the patella was drawn. If the posterior condylar line was drawn on a different slice than the slice with maximal patellar width, the posterior condylar line was copied to the slice where the patella width was maximal. Different angles were noted to best define the patella-trochlear articulation: 1) bisect offset: it was defined as the percentage of the patella lateral to the line through the center of the trochlea (Fig. 2), 2) lateral patella tilt angle: it was defined as the angle between the posterior condylar line and the line defining the maximal width of the patell, 3) Laurin angle: it is the angle between the lines drawn along the lateral patellar facet and the anterior margins of femoral trochlea. 4) congruence angle: it is comprised between a line bisecting the sulcus angle and a second line joining the apex of trochlear groove with the apex of the patella.

View Article: PubMed Central - PubMed

ABSTRACT

Purpose: Patellofemoral instability is a common cause of anterior knee pain in adolescents and young adults. Most normal and pathological values for diagnosing patellofemoral instability are based on Western literature. We conducted this radiological study to determine normal values for different patellofemoral parameters in a Korean population and to evaluate their usefulness in diagnosis.

Materials and methods: We retrospectively reviewed the rotational profile computerized tomography (CT) scans of the patellar dislocation and control groups. Trochlear, patellar, rotational profile, and trochleo-patellar alignment parameters were compared between the groups. Receiver operating characteristic curves were drawn for significant parameters, and sensitivity and specificity were calculated for the cut-off values.

Results: There were 48 patients in the patellar dislocation group and 87 patients in the control group. In the control group and patellar dislocation group, the mean sulcus angle was 132.5° and 143.3°, respectively, trochlear depth was 6.04 mm and 3.6 mm, bisect offset was 56.4% and 99.9%, lateral patellar tilting was 9.8° and 19.2°, patellar facet asymmetry was 63.5% and 45.16%, and the tibial tuberosity-trochlear groove (TT-TG) distance was 10.91 mm and 27.16 mm, respectively.

Conclusions: The trochlear depth, bisect offset, patella tilting, and TT-TG distance were parameters that significantly contributed to patellar instability. Rotational profile CT can be considered a good diagnostic tool to assess all these parameters that help to identify anatomical aberration resulting in patellofemoral instability, thereby helping in formulating the most effective treatment plan.

No MeSH data available.